<%@ Page Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true" CodeFile="Default2.aspx.cs" Inherits="Default2" Title="Untitled Page" %>
<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Data.SqlClient" %>
<%@ Import Namespace="System.Web.UI.WebControls" %>
<asp:Content ID="Content1" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server">
<script runat="server">

  void PopulateNode(Object sender, TreeNodeEventArgs e)
  {

    // Call the appropriate method to populate a node at a particular level.
    switch(e.Node.Depth)
    {
      case 0:
        // Populate the first-level nodes.
        PopulateDepartments(e.Node);
        break;
      case 1:
        // Populate the second-level nodes.
        PopulateCategories(e.Node);
        break;
      default:
        // Do nothing.
        break;
    }

  }

  void PopulateDepartments(TreeNode node)
  {

    // Query for the product categories. These are the values
    // for the second-level nodes.
    DataSet ResultSet = RunQuery("Select DepartmentID, Name From Department");

    // Create the second-level nodes.
    if(ResultSet.Tables.Count > 0)
    {

      // Iterate through and create a new node for each row in the query results.
      // Notice that the query results are stored in the table of the DataSet.
      foreach (DataRow row in ResultSet.Tables[0].Rows)
      {

        // Create the new node. Notice that the CategoryId is stored in the Value property 
        // of the node. This will make querying for items in a specific category easier when
        // the third-level nodes are created. 
        TreeNode newNode = new TreeNode();
        newNode.Text = row["Name"].ToString(); 
        newNode.Value = row["DepartmentID"].ToString();
        newNode.NavigateUrl = "../Catalog.aspx?" + "DepartmentID=" + newNode.Value;      

        // Set the PopulateOnDemand property to true so that the child nodes can be 
        // dynamically populated.
        newNode.PopulateOnDemand = true;

        // Set additional properties for the node.
        newNode.SelectAction = TreeNodeSelectAction.SelectExpand;

        // Add the new node to the ChildNodes collection of the parent node.
        node.ChildNodes.Add(newNode);

      }

    }

  }

  void PopulateCategories(TreeNode node)
  {

    // Query for the products of the current category. These are the values
    // for the third-level nodes.
    DataSet ResultSet = RunQuery("Select CategoryID, Name From Category Where DepartmentID=" + node.Value);
    string departmentId = node.Value;
    // Create the third-level nodes.
    if(ResultSet.Tables.Count > 0)
    {

      // Iterate through and create a new node for each row in the query results.
      // Notice that the query results are stored in the table of the DataSet.
      foreach (DataRow row in ResultSet.Tables[0].Rows)
      {

        // Create the new node.
          TreeNode NewNode = new TreeNode();
          NewNode.Text = row["Name"].ToString();
          NewNode.Value = row["CategoryID"].ToString();
          NewNode.NavigateUrl = "../Catalog.aspx?" + "DepartmentID=" + departmentId +
          "&CategoryID=" + NewNode.Value;
          
            //(row["Name"].ToString());

        // Set the PopulateOnDemand property to false, because these are leaf nodes and
        // do not need to be populated.
        NewNode.PopulateOnDemand = false;

        // Set additional properties for the node.
        NewNode.SelectAction = TreeNodeSelectAction.Select;

        // Add the new node to the ChildNodes collection of the parent node.
        node.ChildNodes.Add(NewNode);
      }
    }

  }

  System.Data.DataSet RunQuery(String QueryString)
  {

    // Declare the connection string. This example uses Microsoft SQL Server 
    // and connects to the Northwind sample database.
      String ConnectionString = "Server=(local)\\sqlExpress;Integrated Security=True;Database=HunterShop"; 

    SqlConnection DBConnection = new SqlConnection(ConnectionString);
    SqlDataAdapter DBAdapter;
    DataSet ResultsDataSet = new DataSet();

    try
    {

      // Run the query and create a DataSet.
      DBAdapter = new SqlDataAdapter(QueryString, DBConnection);
      DBAdapter.Fill(ResultsDataSet);

      // Close the database connection.
      DBConnection.Close();

    }
    catch(Exception ex)
    {

      // Close the database connection if it is still open.
      if(DBConnection.State == ConnectionState.Open)
      {
        DBConnection.Close();
      }

      Message.Text = "Unable to connect to the database.";

    }

    return ResultsDataSet;

  }

</script>


      <h3>TreeView PopulateNodesFromClient Example</h3>

<asp:TreeView id="LinksTreeView"
        Font-Names= "Arial"
        ForeColor="Blue"
        EnableClientScript="true"
        PopulateNodesFromClient="true"  
        OnTreeNodePopulate="PopulateNode"
        ExpandDepth="0"
        runat="server">


      <Nodes>

          <asp:TreeNode Text="Menu" 
             SelectAction="SelectExpand" 
            PopulateOnDemand="true"
           
           />

        </Nodes> 
      </asp:TreeView>

      <br /><br />

      <asp:Label id="Message" runat="server"/>

</asp:Content>

